1. Field Of The Invention
The present invention relates to an integrated and force balanced accelerometer of the closed loop type. More particularly, this invention pertains to an integrated accelerometer formed within a semiconductor substrate that includes associated servo and signal processing electronics formed within a common substrate.
2. Description Of The Prior Art
The integration of sensors and associated signal processing circuitry on a single silicon chip began with pressure transducers about ten years ago. Intensive efforts are currently underway at several universities and industrial research laboratories to extend this technology to many applications including accelerometers.
To date, accelerometers of the open loop type have been built and tested. Typical of such open loop designs are those that include a cantilevered beam constructed from a semiconductor substrate that has an inertial mass attached to its free end. Disposed on opposite sides of such a cantilevered structure are piezoresistive sensing elements. The electrical resistance of such sensing elements vary as the mass moves in response to acceleration forces, stressing the cantilevered beam. Such open loop accelerometers are hampered by poor null stability, high hysteresis and excessive temperature sensitivity.